Oil getting in spark plugs, do i need a head gasket? What is cost of repairs?

What is your question?

If i continue to buy spark plugs, replacing the damp oil ones the car will start. If i need a head gasket, will the cost of repairs, be expensive? and how much if you know? Every time new plugs is replaced they r getting wet or damp from oil getting in plugs. The only way i can get the car to start and run for a short while at least for two weeks is to keep replacing spark plugs.